[ Launch: perpendicular tangent on path ] 137845deaa0ff77abaeb by enjalot
[ Launch: tangent ] ce4c4409fb80559de2bd by enjalot
[ Launch: sampling ] 811484fa83dab4291a2a by enjalot
[ Launch: sampling ] ae8f1e9e966533a0e2e2 by enjalot
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phat path
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{"description":"phat path","endpoint":"","display":"svg","public":true,"require":[],"fileconfigs":{"inlet.js":{"default":true,"vim":false,"emacs":false,"fontSize":12},"_.md":{"default":true,"vim":false,"emacs":false,"fontSize":12},"config.json":{"default":true,"vim":false,"emacs":false,"fontSize":12},"style.css":{"default":true,"vim":false,"emacs":false,"fontSize":12}},"fullscreen":false,"play":false,"loop":false,"restart":false,"autoinit":true,"pause":true,"loop_type":"pingpong","bv":false,"nclones":15,"clone_opacity":0.4,"duration":3000,"ease":"linear","dt":0.01,"ajax-caching":true,"thumbnail":"http://i.imgur.com/d9s5GuB.png","inline-console":false,"controls":{"Amplitude Top":100,"tang":100,"tangent":52,"tangent at":50,"tangent at ":50,"tangent at percent":59}} |
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var height = 150; | |
var points = [ | |
{x: 100, y: 100}, | |
{x: 185, y: 153}, | |
{x: 300, y: 82}, | |
{x: 474, y: 190} | |
] | |
// lets use percentage of the length to determine where we take tangent; | |
var tangentAt = 38; | |
// the amount to phatten the path by | |
var vectorScale = 20; | |
// the number of samples | |
var numSamples = 89 | |
var line = d3.svg.line() | |
.x(function(d) { return d.x }) | |
.y(function(d) { return d.y }) | |
.interpolate("cardinal") | |
//.interpolate("basis") | |
var svg = d3.select("svg") | |
var path = svg.append("path") | |
.attr("d", line(points)) | |
.style({ | |
fill: "none", | |
stroke: "#000", | |
"stroke-width": 4 | |
}) | |
// we get the DOM node | |
var pathNode = path.node(); | |
var tangent = getTangent(pathNode, tangentAt); | |
tangent.v.x *= vectorScale | |
tangent.v.y *= vectorScale | |
console.log(tangent) | |
var perp = rotate2d(tangent.v, 90); | |
svg.append("line") | |
.attr({ | |
x1: tangent.p.x, | |
y1: tangent.p.y, | |
x2: tangent.p.x + tangent.v.x, | |
y2: tangent.p.y + tangent.v.y, | |
stroke: "#e15555", | |
"stroke-width": 2 | |
}) | |
svg.append("line") | |
.attr({ | |
x1: tangent.p.x, | |
y1: tangent.p.y, | |
x2: tangent.p.x + perp.x, | |
y2: tangent.p.y + perp.y, | |
stroke: "#5f55e1", | |
"stroke-width": 2 | |
}) | |
var circles = svg.selectAll("circle") | |
.data(points) | |
.enter().append("circle") | |
.attr({ | |
cx: function(d) { return d.x }, | |
cy: function(d) { return d.y }, | |
r: 5, | |
fill: "none", | |
stroke: "#6d6d6d" | |
}) | |
var node = path.node() | |
var samples = getSamples(node, numSamples); | |
var line90 = d3.svg.line() | |
.x(function(d) { return d.point.x + d.perp.x }) | |
.y(function(d) { return d.point.y + d.perp.y }) | |
.interpolate("cardinal") | |
var line270 = d3.svg.line() | |
.x(function(d) { return d.point.x - d.perp.x }) | |
.y(function(d) { return d.point.y - d.perp.y }) | |
.interpolate("cardinal") | |
var path90 = svg.append("path") | |
.attr("d", line90(samples)) | |
.style({ | |
fill: "none", | |
stroke: "#d725e4", | |
"stroke-width": 1 | |
}) | |
var path270 = svg.append("path") | |
.attr("d", line270(samples)) | |
.style({ | |
fill: "none", | |
stroke: "#25dde4", | |
"stroke-width": 1 | |
}) | |
/* | |
svg.selectAll("line.tangent") | |
.data(samples) | |
.enter() | |
.append("line").classed("tangent", true) | |
.attr({ | |
x1: function(d) { return d.point.x }, | |
y1: function(d) { return d.point.y }, | |
x2: function(d) { return d.point.x + d.tangent.v.x }, | |
y2: function(d) { return d.point.y + d.tangent.v.y }, | |
stroke: "#e15555", | |
"stroke-width": 1 | |
}) | |
*/ | |
svg.selectAll("line.perp") | |
.data(samples) | |
.enter() | |
.append("line").classed("tangent", true) | |
.attr({ | |
x1: function(d) { return d.point.x - d.perp.x }, | |
y1: function(d) { return d.point.y - d.perp.y }, | |
x2: function(d) { return d.point.x + d.perp.x }, | |
y2: function(d) { return d.point.y + d.perp.y }, | |
stroke: "#5f55e1", | |
"stroke-width": 3, | |
"stroke-opacity": 0.5, | |
"stroke-linecap": "round" | |
}) | |
/* | |
var rects = svg.selectAll("rect") | |
.data(samples) | |
.enter().append("rect") | |
.attr({ | |
x: function(d) { return d.point.x }, | |
y: function(d) { return d.point.y }, | |
width: 5, | |
height: function(d) { return 10 } | |
}) | |
*/ | |
function getSamples(path, num) { | |
var len = path.getTotalLength() | |
var p, t; | |
var result = [] | |
for(var i = 0; i < num; i++) { | |
p = path.getPointAtLength(i * len/num); | |
t = getTangent(path, i/num * 100); | |
t.v.x *= vectorScale | |
t.v.y *= vectorScale | |
result.push({ | |
point: p, | |
tangent: t, | |
perp: rotate2d(t.v, 90) | |
}); | |
} | |
return result | |
} | |
function getTangent(path, percent) { | |
// returns a normalized vector that describes the tangent | |
// at the point that is found at *percent* of the path's length | |
var fraction = percent/100; | |
if(fraction < 0) fraction = 0; | |
if(fraction > 0.99) fraction = 1; | |
var len = path.getTotalLength(); | |
var point1 = path.getPointAtLength(fraction * len - 0.1); | |
var point2 = path.getPointAtLength(fraction * len + 0.1); | |
var vector = { x: point2.x - point1.x, y: point2.y - point1.y } | |
var magnitude = Math.sqrt(vector.x*vector.x + vector.y*vector.y); | |
vector.x /= magnitude; | |
vector.y /= magnitude; | |
return {p: point1, v: vector }; | |
} | |
function rotate2d(vector, angle) { | |
//rotate a vector | |
angle *= Math.PI/180; //convert to radians | |
return { | |
x: vector.x * Math.cos(angle) - vector.y * Math.sin(angle), | |
y: vector.x * Math.sin(angle) + vector.y * Math.cos(angle) | |
} | |
} | |
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#display { | |
background: white | |
} |
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